The matrix A = 0 0 -4 0 1 0 1 20 A = can be reduced down to the identity in the following three steps 0 0 1 0 1 0 -4 0 20 (a) What are the three elementary row operations used in order. (b) Using part (a), find elementary matrices E, E2 and E3 such that E3 E E A = I. (c) Write A- as a product of elementary matrices. Leave your answer as the product. Do not multiply. (d) Write A as a product of elementary matrices. Leave your answer as the product. Do not multiply. 0 0 1 0 0 0 -5 0 1 1 0 1 0 0 1 10 1 0 0 1 0 0 0 0 = I